Abstract: The present invention relates to methods and systems of snapshot management of a file system in a data storage system. To represent the snapshots, the invention maintains pointers to the root block pointer of each snapshot. When the active file system is modified, this invention avoids overwriting any blocks used by previous snapshots by allocating new blocks for the modified blocks. When the invention needs to put an established block in a new location, it must update a parent block to point to the new location. The update to the parent block may then require allocating a new block for the new parent block and so forth. Parts of the file system not modified since a snapshot remain in place. The amount of space required to represent snapshots scales with the fraction of the file system that users modify. To maintain snapshot integrity, this invention keeps track of the first and last snapshots that use each block in space map blocks spread throughout the file system data space.

Abstract: The invention relates to a multiple QoS file system and methods of processing files at different QoS according to rules. The invention allocates multiple VLUNs at different qualities of service to the multiQoS file system. Using the rules, the file system chooses an initial QoS for a file when created. Thereafter, the file system moves files to different QoS using rules. Users of the file system see a single unified space of files, while administrators place files on storage with the new cost and performance according to attributes of the files. A multiQoS file system enhances the descriptive information for each file to contain the chosen QoS for the file.

Abstract: The present invention relates to methods and systems of snapshot management of a file system in a data storage system. To represent the snapshots, the invention maintains pointers to the root block pointer of each snapshot. When the active file system is modified, this invention avoids overwriting any blocks used by previous snapshots by allocating new blocks for the modified blocks. When the invention needs to put an established block in a new location, it must update a parent block to point to the new location. The update to the parent block may then require allocating a new block for the new parent block and so forth. Parts of the file system not modified since a snapshot remain in place. The amount of space required to represent snapshots scales with the fraction of the file system that users modify. To maintain snapshot integrity, this invention keeps track of the first and last snapshots that use each block in space map blocks spread throughout the file system data space.

Abstract: The present invention relates to methods and systems of snapshot management of a file system in a data storage system. To represent the snapshots, the invention maintains pointers to the root block pointer of each snapshot. When the active file system is modified, this invention avoids overwriting any blocks used by previous snapshots by allocating new blocks for the modified blocks. When the invention needs to put an established block in a new location, it must update a parent block to point to the new location. The update to the parent block may then require allocating a new block for the new parent block and so forth. Parts of the file system not modified since a snapshot remain in place. The amount of space required to represent snapshots scales with the fraction of the file system that users modify. To maintain snapshot integrity, this invention keeps track of the first and last snapshots that use each block in space map blocks spread throughout the file system data space.

Abstract: The present invention relates to system and method of asynchronous data replication. In an embodiment, the system includes a primary host that asynchronously transmits write and sync commands where each write and sync command includes a data set ID and a sequence number. A secondary host coupled to the primary host receives the write and sync commands out of order, tracks receipt of write and sync commands, and after receipt of the write and sync commands of the data set writes blocks associated with the write commands to data storage coupled to the secondary host.

Abstract: The present invention relates to methods and systems of snapshot management of a file system in a data storage system. To represent the snapshots, the invention maintains pointers to the root block pointer of each snapshot. When the active file system is modified, this invention avoids overwriting any blocks used by previous snapshots by allocating new blocks for the modified blocks. When the invention needs to put an established block in a new location, it must update a parent block to point to the new location. The update to the parent block may then require allocating a new block for the new parent block and so forth. Parts of the file system not modified since a snapshot remain in place. The amount of space required to represent snapshots scales with the fraction of the file system that users modify. To maintain snapshot integrity, this invention keeps track of the first and last snapshots that use each block in space map blocks spread throughout the file system data space.

Abstract: Local transactions are run at replication sites while receiving and tracking replication packages from primary sites. If a package coming in from a primary site updates data that a local transaction used, the data is considered stale and the local transaction is restarted. When the replication site wishes to commit (e.g., update data at the primary sites), a special dummy marker is submitted and committed. The marker comprises a dummy transaction that updates a piece of data at the primary site private to the replication site. The local site waits for the dummy transaction in the stream of replication packages sent from the primary site. Once the dummy transaction is received, the replication site is assured that any subsequent replication packages from the primary site will not affect the local transaction. If the replication packages received before the marker do not affect data items referenced during the local transaction, the local transaction commits.

Abstract: A standardized message processing procedure is invoked by an application program to generate informative messages. Message repositories are provided in files accessible to the message processor. A separate repository is provided for each national language which is supported. The application invokes the message processor, passing variable information for inclusion in a message. The message processor retrieves the message syntax and fixed fields from the appropriate repository, assembles the message using information from the repository and information provided by the invoking application, and generates the message. A preprocessor can be used to generate the repository files, and macros suitable for inclusion in application source files to invoke the message processor.

Abstract: A method for increasing throughput of N-way central electronic complexes concurrently executing processes to selectively lockable data resources while maintaining coherency among replicates of the information state of any accessed resource. Throughput is increased by overlapping a resource lock request with the processing incidental to accessing the resource. Processes are granted locks to portions of the resource based on the interest state held by the central electronic complex in the resource. Messages are attached to locked resources and are distributed to the appropriate complexes by virtue of a list maintained by the central electronic complex holding sole interest in the resource. The central electronic complex distributing the messages must receive acknowledgement of the message reception before releasing the resource.